[jonesy814]

A little less valuable than a plain one. I'd say around $550 to $600 max.

I think you are a little out of touch with current pricing. Tough to find any 586 for under $700 these days
A brand new 686 will run you $900 these days and a 586 is more like $1000

Has there been a lot of stocks with that cut out on the right side? That is something new to me. A little personal customization ? Or am I exaggerating ?

Those are typical of presentation stocks from the early 80's. Curt360 has a PA State Police commemorative model 19 with the same style stocks